1. Field of the Invention
The invention relates to an optical beam-shaping system with optical elements arranged in a radiation bundle, said elements having lens arrays each having a plurality of lenses each sensing partial radial bundles, whereby the surfaces of said lenses are shaped into an optically active interface of a monolithic refractive element.
2. The Prior Art
Optical beam-shaping systems generally are arrangements of optical elements by which a bundle of rays of light irradiated upon such elements is modified in a defined way with respect to its beam parameters. It is required in the main cases of practical application that a bundle of rays has a defined geometric shape and size with respect to its cross section, for example a circular, rectangular or lattice-like shape or the like, and/or an intensity distribution defined across its cross section. Both properties frequently have to be influenced simultaneously, for example if the light source delivering the incoming bundle of rays for the beam-shaping system supplies a bundle of rays with irregular intensity distribution and irregular geometric dimensions, but defined specifications have to be satisfied for the outgoing bundle of rays of the beam-shaping system with respect to its properties.
According to the state of the art, optical beam-shaping systems are known from EO 0 232 037 A2 in which a bundle of light rays can be irradiated into the system with irregular energy distribution, whereby their outgoing bundle of rays has a uniform intensity distribution over its cross section. Such beam-shaping systems are referred to also as homogenizers.
In addition to conventional optical elements such as, for example collecting lenses with positively curved, i.e. convex boundary surfaces, which detect the total cross section of the admitted bundle of rays, said homogenizer also has so-called lens arrays, which are composed of lenses which each only sense a part of the cross section of the beam, i.e., partial radial bundles.
A design has successfully gained acceptance in connection with optical homogenizers where cylinder lens arrays that are crossed relative to each other are arranged in the path of the rays. Said arrays are partly still assembled from individual cylinder lens elements; however, simple plane cylinder lens arrays are already available as well, which are ground from a monolithic block of glass or plastic.
However, with such monolithic optical elements as known according to the prior art, it has been possible heretofore to exclusively realize only homogenizers which additionally require the use of additional optical elements such as lenses or the like. However, in order to obtain not only an intensity distribution that has been made uniform over the cross section as with the homogenizer, but to also shape a defined intensity profile in a defined geometric from starting out from incoming bundles of rays of any shape, it is necessary according to the state of the art to first homogenize the incoming beam in order to then interconnect additional beam-shaping systems in the further course of the beam. It is known, for example, to preset an intensity profile by employing absorption filters or masks. A geometric shaping of the beam is accomplished by inserting correspondingly shaped masks in the path of the beam.
The drawback of the aforementioned geometric and intensity beam-shaping systems is obvious: the by far predominating part of the admitted radiation energy is absorbed in filters or in the impermeable regions of the masks and consequently no longer available as light energy in the outgoing bundle of rays. In the practical application of beam-shaping systems according to the state of the art, more than 90% of the energy irradiated into the system is lost in this way. The overall efficiency of such systems is consequently poor.
Furthermore, the known optical beam-shaping systems including the aforementioned homogenizers are assembled in each case from a multitude of structural optical elements, with the result that their manufacture and adjustment are complicated and costly.